Electronic locks particularly as secure closures for doors are becoming more popular. However a major defect is that such locks, when battery powered, become operationally inaccessible when the battery power is depleted. Access to entry remains unavailable or difficult until the battery is changed or recharged and the electronic lock control is enabled. Accordingly, such locks are often provided with an overriding mechanical key function whereby an available mechanical key can be used to open the lock. Separate secure storage of the mechanical key in a proximate location for ready use has been used with expedients such as unsightly separate storage places for the emergency key and the like. However, the separate sites are often difficult to find or access. Charging of a discharged battery is not feasible when immediate entry access is required and spare batteries are very difficult to find or to store in a readily accessible manner.